H7N3亚型禽流感病毒感染人

20 0 4年3月,加拿大CFIA(Canadian Food Inspection Agency)的1名工作人员在视察Fraser Valley地区暴发H7N3亚型禽流感的养鸡场后,出现了结膜炎和喉痛、咳嗽等上呼吸道症状。经实验室确认,该工作人员感染了H7N3亚型禽感染病毒。2 0 0 4年4月2日,该地区确诊了第2名感染H7N3禽流感病毒的工作人员。目前这2名工作人员均已经完全恢复健康。对于H7亚型禽流感病毒,此前曾有H7N7感染人的报道,而且都恢复了健康。这H7N3感染人的事件发生后,该地区对与病禽接触的工作人员采取了加强个人防护、口服Tamiflu和免疫流感疫苗等一系列措施。其他10…     

北美H7亚型禽流感病毒RT-PCR检测方法的建立

本研究通过分析NCBI数据库中H7亚型禽流感病毒HA基因序列,根据该基因设计引物,建立了针对北美H7亚型禽流感病毒HA基因的一步法RT-PCR检测方法,并对反应条件进行了优化。该方法可特异地检出北美H7亚型禽流感病毒HA基因,而未检出欧亚分支H7亚型禽流感病毒H7N2和H7N9、其他亚型流感病毒(H1N1、H3N2、H5N1、H5N8和H9N2),以及新城疫病毒和鸡传染性支气管炎病毒;检测方法的灵敏度可达0.1 pg/μL。该检测方法的建立为监测北美H7亚型禽流感病毒提供了良好的技术支撑,可用于外来禽流感病毒的检测。     

禽流感病毒H5、H7和H9亚型一步法多重RT-PCR检测方法的建立

为了建立能同时检测H5、H7和H9亚型禽流感病毒(AIV)的方法,参考GenBank中H5、H7和H9亚型AIV的HA基因序列的保守区域,利用Primer 5.0软件设计3对分别针对AIV H5、H7和H9亚型的特异性引物,预期特异扩增H5AIV片段大小为380bp、H7AIV为501bp、H9AIV为732bp。经过反应条件的优化,建立了同时检测H5、H7和H9亚型AIV的一步法多重RT-PCR方法。该方法特异性强,对其他亚型AIV和禽呼吸道病原体检测结果为阴性;敏感性高,H5、H7和H9亚型AIV RNA的最低检出量分别为10-4、10-4、10-2拷贝/μL。初步建立了快速、敏感、特异地鉴别检测H5、H7和H9亚型禽流感病毒的分子生物学诊断方法。     

H1和H3亚型禽流感病毒二重PCR检测方法的建立

为建立简便、快速同时检测H1和H3亚型禽流感病毒(Avian influenza virus,AIV)的方法,根据GenBank中H1亚型AIV-HA基因和H3亚型AIV-HA基因的序列,分别设计了2对针对H1AIV和H3 AIV的保守基因序列的引物.应用这2对引物对混有H1 AIV和H3 AIV的模板进行二重PCR扩增,得到了2个特异性扩增条带,大小与试验设计相符的302 bp(H1 AIV)和626 bp(H3 AIV),而对其他亚型AIV和禽呼吸道病原体的PCR扩增结果均为阴性,敏感性测定结果表明,该二重PCR技术能同时检出50Pg的H1 AIV模板和26 pg的H3 AIV模板.     

禽流感病毒H7亚型竞争ELISA抗体检测方法的建立

将禽流感病毒H7亚型标准抗原作为免疫原免疫BALB/c小鼠,取免疫合格的脾细胞与骨髓瘤细胞(SP2/0)进行融合。通过血凝抑制试验,筛选得到12株杂交瘤细胞上清具有HI效价,且与禽流感病毒H7亚型阳性血清间具有较好的竞争效果。将竞争效果最好的1H11细胞扩大培养后制备腹水,获得的单克隆抗体具有效价高、特异性好等特点。使用H7标准抗原包被ELISA板,将HRP标记的单克隆抗体作为竞争抗体,建立了一种禽流感病毒H7亚型竞争ELISA抗体检测方法。利用该方法对待检血清进行测试,与HI试验有99.3%的符合率,说明试制的禽流感病毒H7亚型竞争ELISA抗体检测试剂盒可以用来检测禽流感病毒H7亚型抗体,且操作简便快捷,可批量操作,大样本检测鸡群抗体水平。     

H7亚型禽流感病毒微滴式数字PCR检测方法的建立及应用

为了建立灵敏、特异的H7亚型禽流感病毒(AIV)微滴式数字PCR(ddPCR)检测方法，本研究根据GenBank和GISAID中H7亚型AIV血凝素(HA)基因的核苷酸序列，设计合成H7亚型AIV的引物和探针，对反应条件进行优化，从而建立检测H7亚型AIV的ddPCR方法，并测定其特异性、敏感性和重复性。结果显示，最佳引物浓度和探针浓度分别为900 nmol/L和250 nmol/L,最佳退火温度为55℃,最佳升降温速率为2.0℃/s,最佳反转录时间为20 min。特异性试验结果显示，该方法仅对H7亚型AIV进行特异性检测，对H5亚型AIV、H9亚型AIV、新城疫病毒、鸡传染性支气管炎病毒、传染性法氏囊病毒均不能检出。敏感性试验结果显示，该方法对重组质粒标准品检测下限为0.8 copies/μL,比荧光定量PCR(qPCR)方法敏感性高10倍。组内和组间重复性试验结果显示，变异系数均小于3%。对60份临床样品检测显示，该方法与鸡胚分离方法的符合率为100%。结果表明，本研究建立的H7亚型AIV ddPCR检测方法具有较好的特异性、重复性和敏感性，可用于H7亚型AIV的早期诊断、流行病学...     

H5、H7和H9亚型禽流感病毒多重反转录聚合酶链式反应检测方法的建立

参考GenBank登录的H5、H7和H9亚型禽流感病毒(AIV)的血凝素基因序列,利用DNAStar软件分析其同源性,利用Primer Premier5.0软件设计3对分别针对AIVH5、H7和H9亚型的特异性引物。3对引物所扩增的cDNA片段大小分别为427、228、830bp。结果显示,利用3对引物,通过对多重RT-PCR扩增条件的优化,建立了同时检测H5、H7和H9亚型AIV的多重RT-PCR技术。该方法对H5、H7和H9亚型AIV能同时扩增出3条大小分别为427、228、830bp的cDNA片段,与其他常见禽病病原不存在交叉反应。该方法对H5、H7和H9亚型AIVcDNA的最低检出量分别为10-4、10-2和10-4。结果表明,本试验建立了可同时检测鉴别H5、H7和H9亚型AIV的多重RT-PCR技术。     

H7亚型禽流感RT-PCR诊断方法的建立

参照GenBank中已发表的H7亚型禽流感病毒血凝素(HA)基因设计合成了一对预计扩增片段大小约为310bp的引物。利用这对引物,通过对RT-PCR反应体系和反应条件的优化,建立了针对H7亚型禽流感的RT-PCR检测方法。敏感性试验和特异性试验结果表明,该方法敏感性高,最低可检出100pg的AIV-H7的mRNA,且应用该引物对新城疫病毒(NDV)、传染性支气管炎病毒(IBV)及其他亚型的流感病毒(H1、H3、H5、H9)在相同反应条件下未扩增出任何片段,具有较好的特异性。用所建立RT-PCR方法检测发病鸡组织病料及咽、肛拭子,检测结果与鸡胚病毒分离结果相比,阳性符合率高达90.6%。     

H3亚型禽流感病毒巢式PCR检测方法的建立

为建立一种H3亚型禽流感病毒(AIV)的检测方法,本研究针对H3亚型AIV HA基因保守序列,设计并筛选出2对特异性引物,通过优化反应条件,建立了H3亚型AIV巢式PCR检测方法。对该法进行特异性和敏感性检验,并用该法对96份临床样品进行检测。特异性试验结果表明该法只能检测到H3亚型AIV,对其他常见禽病病原体不扩增;敏感性试验结果表明该巢式PCR对H3亚型AIV检测下限为1×10³拷贝/μL,灵敏度比常规PCR高100倍;96份临床样品检测结果与病毒分离结果一致。本研究所建立的巢式PCR为H3亚型AIV的诊断提供了一种准确、有效的检测方法。     

H7亚型禽流感病毒实时荧光定量RT-PCR检测方法的建立

H7亚型禽流感病毒致病性强、危害性大,是进出口家禽及禽类产品的主要检疫对象。为了加强对H7亚型禽流感病毒的检测,建立新的快速检测方法。通过对GenBank已报道的H7亚型禽流感病毒的HA基因进行序列分析比较,设计了两套分别针对H7N2亚型和H7Nx亚型的特异性引物和用FAM标记的Taq Man MGB核酸探针,建立了H7亚型禽流感病毒实时荧光定量RT-PCR方法(Real-time RT-PCR)。该方法特异性好,不存在假阴性和假阳性的现象;敏感性高,对禽流感病毒H7亚型标准HI抗原检测的敏感性达到10-5,能够满足口岸禽流感病毒快速、准确、有效的检疫需求。     

禽流感病毒H5HA、H7HA、H9HA亚型夹心ELISA方法的建立

将禽流感病毒(AIV)H5、H7、H9血凝素亚型标准血清中的IgG作为包被抗体,H5、H7、H9血凝素亚型单克隆抗体作为第二抗体,建立了双抗体夹心ELISA(AC-ELISA)方法,并优化了反应条件.结果表明:单抗和标准血清最适工作质量浓度分别为5、10 mg/L,标准阳性血清于4℃包被12 h,二抗作用条件为37℃作用1 h,封闭条件为37℃作用1 h,酶标抗体工作条件为1∶5 000稀释后,37℃作用1 h,底物作用条件为37℃作用10 min.阴阳性抗原临界值为0.274～0.332.本方法具有很高的特异性和敏感性.     

H9亚型禽流感病毒免疫层析快速检测试剂盒的研制及应用

利用胶体金免疫层析技术,在建立H9亚型禽流感病毒免疫层析检测方法的基础上组装成试剂盒.试剂盒由试纸卡,稀释液、样品管、塑料吸管、一次性手套及说明书组成.对试剂盒的特异性、敏感性、保存期和重复性等进行了测定.结果表明,试剂盒在室温可以保存6个月,4℃可以保存12个月;与HA试验相比特异性强、灵敏度高、重复性好,操作简单、方便、快捷,能在10 min内准确检测出样品中是否含有H9亚型禽流感病毒.先后制备了5批试剂盒,对武汉市及周边地区的鸡场共抽检498份样品,经病毒分离鉴定准确率达到100%.     

An enzyme-linked immunosorbent assay for detection of avian influenza virus subtypes H5 and H7 antibodies

Background

Avian influenza virus (AIV) subtypes H5 and H7 attracts particular attention because of the risk of their potential pathogenicity in poultry. The haemagglutination inhibition (HI) test is widely used as subtype specific test for serological diagnostics despite the laborious nature of this method. However, enzyme-linked immunosorbent assays (ELISAs) are being explored as an alternative test method.H5 and H7 specific monoclonal antibodies were experimentally raised and used in the development of inhibition ELISAs for detection of serological response specifically directed against AIV subtypes H5 and H7. The ELISAs were evaluated with polyclonal chicken anti-AIV antibodies against AIV subtypes: H1N2, H5N2, H5N7, H7N1, H7N7, H9N9, H10N4 and H16N3.

Results

Both the H5 and H7 ELISA proved to have a high sensitivity and specificity and the ELISAs detected H5 and H7 antibodies earlier during experimental infection than the HI test did. The reproducibility of the ELISA’s performed at different times was high with Pearson correlation coefficients of 0.96-0.98.

Conclusions

The ELISAs are a potential alternative to the HI test for screening of large amounts of avian sera, although only experimental sera were tested in this study.     

H10亚型和N8亚型禽流感病毒双重RT-PCR检测方法的建立

根据Gen Bank中H10亚型和N8亚型禽流感病毒(AIV)的HA和NA基因保守序列,分别设计筛选出2对特异性引物,用于H10亚型和N8亚型AIV的检测,优化引物之间的浓度,建立了同时检测H10亚型和N8亚型AIV的双重RT-PCR检测方法。该方法对H10N8亚型AIV可特异性扩增出267 bp(H10亚型)和464 bp(N8亚型)目的条带,对H10Ny(y≠8)亚型AIV仅扩增出267 bp目的条带,对HXN8(x≠10)亚型AIV仅扩增出464 bp目的条带,对其他亚型AIV和常见禽病病原体均未扩增出任何条带。该方法对H10亚型和N8亚型AIV检测下限均为104拷贝数/μL。本研究建立的H10亚型和N8亚型AIV双重RT-PCR特异性强、灵敏度高,可同时快速检测H10亚型和N8亚型AIV,为其感染的快速鉴别诊断提供一种简便、快速和有效的方法。     

Development and evaluation of a DAS-ELISA for rapid detection of avian influenza viruses

Rapid detection of avian influenza virus (AIV) infection is critical for control of avian influenza (AI) and for reducing the risk of pandemic human influenza. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was developed for this purpose. The method employed a monoclonal antibody (MAb) as the capture antibody and rabbit polyclonal IgG labeled with horseradish peroxidase as the detector antibody, and both antibodies were against type-specific influenza A nucleoprotein (NP). The DAS-ELISA could detect minimally 2.5 ng of influenza viral protein in virus preparations treated with Triton X-100, which is equvilent to 2.5 x 10(2) EID50 virus particles. This DAS-ELISA could detect all 15n AIV subtypes (H1-H15) and did not cross react with other avian pathogens tested. The DAS-ELISA were directly compared with virus isolation (VI) in embryonated chicken eggs, the current standard of influenza virus detection, for 805 chicken samples. The DAS-ELISA results correlated with VI results for 98.6% of these samples, indicating a sensitivity of 97.4% and specificity of 100%. The method was further tested with H5N1 and H9N2 AIV experimentally infected chickens, ducks, and pigeons, as well as field samples obtained from central China in 2005. The DAS-ELISA method has demonstrated application potential as an AIV screening tool and as a supplement for virus isolation in Asia.     

Evolution of highly pathogenic H7N3 avian influenza viruses in Mexico

Highly pathogenic H7N3 influenza A viruses have persisted in poultry in Mexico since 2012, diversifying into multiple lineages that have spread to three Mexican states, as of 2016. The H7N3 viruses segregate into three distinct clades that are geographically structured. All 2016 viruses are resistant to adamantane antiviral drugs and have an extended 24‐nucleotide insertion at the HA cleavage site that was acquired from host 28S ribosomal RNA.     

Molecular characterization of low pathogenicity H7N3 avian influenza viruses isolated in Italy

The complete coding regions of the surface glycoproteins, nucleoprotein (NP), polymerase 2 (PB2), and matrix (M) of A/turkey/214845/02 and A/turkey/220158/99 (H7N3) low pathogenicity avian influenza (LPAI) viruses isolated in October 2002 in Italy were amplified and sequenced to determine the epidemiologic relationships with an A/turkey/Italy/4603/99 (H7N1/4603/99) LPAI virus isolated during the 1999-2001 epizootic in Italy. The hemagglutinin (HA) of H7N3 viruses showed 97.8% nucleotide similarity with A/turkey/Italy/4603/99 (H7N1), and NP, M, and PB2 gene similarities were 93.6%, 98.2%, and 96.2%, respectively. Phylogenetic analyses of HA, PB2, and M genes showed that H7N3 and H7N1 viruses were closely related. Sequence analysis revealed a 23 amino acid deletion in the stalk of the neuraminidase of H7N3 viruses and a unique deletion of amino acid glycine in position 17 in the NP gene of H7N1 virus.